Exertional symptoms in symptomatic patients with aortic stenosis have been attributed to abnormal exercise hemodynamics. In order to assess exercise hemodynamics in asymptomatic patients with aortic stenosis, 11 patients (valve gradient 64+-31 mmHg by Doppler) underwent symptom limited exercise (Bruce protocol) with intraarterial blood pressure monitoring. Rest and maximum systolic blood pressure, percent of predicted maximum oxygen consumption, percent of predicted maximum 02 pulse (an index of stroke volume), exercise duration, age, and maximum heart rate were compared to 25 controls of similar age distribution. Compared to the controls, the asymptomatic patients with aortic stenosis achieved a lower systolic blood pressure, a lower percent of predicted oxygen consumption, and a lower percent of predicted oxygen pulse. All but one patient stopped because of fatigue; the remaining patient complained of lightheadedness. No patient developed exercise-induced hypotension. Thus, aortic stenosis patients show impaired hemodynamic responses to upright exercise, even when asymptomatic.